The overall objectives of this project are to identify and understand the role of cellular immune responses in the control of the incidence and spread of cancer of the urinary bladder. To achieve these objectives, we have been looking at both the general immune responsiveness of bladder cancer patients and their tumor-specific immune responses. For measures of the general immune responsiveness of patients we have been studying Mixed Leukocyte Culture responses and responses to mitogens PHA and Con-A. In addition, we have been looking at the ability of blood leukocytes from bladder cancer patients to stimulate in Mixed Leukocyte Culture. Our aim in those studies is to identify and then to thoroughly investigate the alterations in immune reactivity of patients. The studies on specific immune reactions revolve around the study of cell-mediated and antibody-dependent cell-mediated cytotoxicity for these bladder cancer patients' tumor cells in culture. The goals for the current year were to further investigate the possibility that suppressor cells in both blood and regional lymph nodes were responsible for the apparent immunodepression or hypo-immune responsiveness of some bladder cancer patient's lymphocytes. In addition, we were to continue developing measures of specific immune reactivity in order to measure the ability of patient's lymphocytes to be toxic for tumor cells in culture. Related to this was the development of an in vitro sensitization model for the development of specifically cytotoxic T cells so that these could be used to define the limits of the various techniques for demonstration of specific immune reactivity, cryopreservation of such active cells, etc.